An awful outdated system still used in many countries such as the US and partly in the UK.

Revolves around measuring weight, length, distance and currency in units that actually do not make sense, unlike the metric system which has been taken on board by most countries and is used in all science.

imperial system : 12 inches is a foot. 3 foot is a yard. 1760 yards is a mile.

metric system : 10 milimetres is a centimetre. 100 centimetres is a metre. 1000 metres is a kilometre.